Integrated Dynamic Response Analysis Of Steel Catenary Riser And Semi-submersible Platform

At present,the exploitation of oil and gas gradually toward the deep sea,in order to adapt to the harsh environment of the deep sea,the need for new production equipment and emerging technologies,and the steel catenary riser with its unique structural advantages has been widely used in offshore oil and gas exploration.The steel catenary riser hanging on the outside of the floating platform,not only to withstand disturbance waves in the marine environment,but also affected by the top of the floating body,we can't study risers as independent component analysis,but as a whole,then we can be more accurate analysis of steel catenary riser dynamic response in the marine environment.Calculate the natural frequency and modal shape of the overall analysis modelIn this paper,the dynamic model of steel catenary riser is established using the virtual work principle,get the equation of motion of the stand pipe combined with the Euler equation and initial condition.Combined the equation of motion for floating platform with the riser motion equation,the overall analysis model is established.Calculate the natural frequency and modal shape of the overall analysis model,on the basis of Newton-Raphson iteration method to calculate SCR displacement and Angle increment,get the static equilibrium location of the riser.Calculated the dynamic response of the SCR caused by wave and floating platform movement.Calculated wave the vertical structure and the dispersion relation of the internal wave,get the wave load and the movement of floating platform,programmed the Matlab analysis program by using the Newmark-? method to calculate the dynamic response of SCR and compared with the traditional coupling model.Calculated the surface wave force and displacement of the floating platform using hydrodynamic analysis software ANSYS WORKBENCH,the results applied to the top of the dynamic model as boundary conditions,calculated and compared analysis results of different model.Study show that the influence of the top tension on the dynamic characteristics and dynamic response is more significant than the internal flow velocity.When the riser resonance occurs,the internal flow velocity can help improve the stability of the riser.Surface wave and floating platform has certain influence on riser vibration frequency,internal waves as a main factor to promote the riser global motion,the vibration displacement of riser is mainly affected by internal wave,the top angle of the SCR is mainly affected by the platform motion.Surface wave acting on the floating platform,through the floating platform movement affects the movement of the riser.The motion of floating platform on the direction of pitching have the largest influence on pipe vibration response during the four degrees of freedom.Through the comparative analysis of the whole analysis model and the traditional coupling model,it is found that the riser vibration law is more clear,the calculation results are relatively significant,and more close to the reality.